Semiconductor device and gate structure having a composite dielectric layer and methods of manufacturing the same

ABSTRACT

A semiconductor device and/or gate structure having a composite dielectric layer and methods of manufacturing the same is provided. In the semiconductor device, gate structure, and methods provided, a first conductive layer may be formed on a substrate. A native oxide layer formed on the first conductive layer may be removed. A surface of the first conductive layer may be nitrided so that the surface may be altered into a nitride layer. A composite dielectric layer including the first and/or second dielectric layers may be formed on the nitride layer. A second conductive layer may be formed on the composite dielectric layer. The first dielectric layer may include a material having a higher dielectric constant. The second dielectric layer may be capable of suppressing crystallization of the first dielectric layer.

PRIORITY STATEMENT

This application claims benefit of priority under 35 USC § 119 fromKorean Patent Application No. 2005-18415, filed on Mar. 5, 2005, in theKorean Intellectual Property Office, the contents of which areincorporated herein by reference in their entity.

BACKGROUND

1. Field of the Invention

Example embodiments of the present invention relate to a semiconductordevice and/or gate structure having a composite dielectric layer andmethods of manufacturing the same. Other example embodiments of thepresent invention relates to a semiconductor device and/or gatestructure having a composite dielectric layer including a materialhaving a higher dielectric constant and methods of manufacturing thesame.

2. Description of the Related Art

Semiconductor devices may be classified as a volatile memory deviceand/or a non-volatile memory device. Examples of volatile memory devicesmay include dynamic random access memory (DRAM) devices and/or staticrandom access memory (SRAM) devices. Examples of non-volatile memorydevices may include read only memory (ROM) devices and electricallyerasable programmable read only memory (EEPROM) devices. Examples ofEEPROMs may include flash memory devices.

Flash memory devices may includes source/drain regions formed in asurface of a substrate (e.g. a silicon wafer), a channel region, atunnel dielectric layer formed on the substrate, a floating gateelectrode formed on the tunnel dielectric layer, a gate dielectric layerformed on the floating gate electrode and/or a control gate electrodeformed on the gate dielectric layer.

An example of a gate dielectric layer may include a composite dielectriclayer having an oxide-nitride-oxide (ONO) structure. In order to achievea higher integration, a dielectric layer of a material, having a higherdielectric constant, may be used as the gate dielectric layer of thenon-volatile memory device instead of the composite dielectric layerhaving the ONO structure. The dielectric layer of the material, havingthe higher dielectric constant, also may be used as a gate layer of ametal oxide semiconductor (MOS) transistor and/or a dielectric layer ofa capacitor. The dielectric layer may be formed of aluminum oxide(Al₂O₃), hafnium oxide (HfO₂) and/or zirconium oxide (ZrO₂).

The conventional art acknowledges that a dielectric layer of zirconiumoxide may be formed by using Zr[N(CH₃) (C₂H₅)]₄ (tetrakis ethyl methylamino zirconium: TEMAZ) as a reaction material. In addition,conventional methods also recognize that a dielectric layer of zirconiumoxide may be formed by using ZrCl₄ as a reaction material.

As known in the conventional art, a dielectric layer, which may includean aluminum oxide layer and/or an alloy layer, may be formed on thealuminum oxide layer. The alloy layer may include tantalum oxide,zirconium oxide, hafnium oxide, hafnium aluminum oxide and/or lanthanumaluminum oxide.

According to conventional methods, a dielectric layer may include asilicate interface layer and/or a layer that may have a dielectricconstant of about 20. The layer may be formed on the silicate interfacelayer. In addition, the layer may be a hafnium oxide layer, a zirconiumoxide layer, a tantalum oxide layer, an aluminum oxide layer, a titaniumoxide layer, an yttrium oxide layer, a BST layer and/or a lead zirconiumtitanate (PZT) layer.

Furthermore, conventional methods of nitriding a surface of a conductivelayer for the formation of a floating gate are known in the art.

SUMMARY OF THE EXAMPLE EMBODIMENTS

Example embodiments of the present invention provide a semiconductordevice and/or gate structure including a composite dielectric layer andmethods of manufacturing the same. Other example embodiments provide asemiconductor device and/or gate structure including a compositedielectric layer with a higher dielectric constant and methods ofmanufacturing the same.

In example embodiments of the present invention, there is provided asemiconductor device which may include a substrate; a tunnel dielectriclayer formed on the substrate; a first conductive layer formed on thetunnel dielectric layer; an oxide layer formed on the first conductivelayer; a nitride layer formed on the first conductive layer, afterremoving the oxide layer, a composite dielectric layer and/or a secondconductive layer formed on the composite dielectric layer. The compositedielectric layer may include a first dielectric layer and/or a seconddielectric layer. The first dielectric layer may include a materialhaving a higher dielectric constant than the second dielectric layer.

In another example embodiment, the second dielectric layer may have acrystallization temperature higher than the first dielectric layer. Inyet another embodiment, the second dielectric layer may retardcrystallization of the first dielectric layer.

According to other example embodiments, the second conductive layer, thecomposite dielectric layer, the nitride layer, the first conductivelayer and/or the tunnel dielectric layer may be patterned to form a gatestructure including a control gate electrode, a composite dielectriclayer pattern, a nitride layer pattern, a floating gate electrode and/ora tunnel dielectric layer pattern.

In accordance with example embodiments of the present invention, thereare provided methods of manufacturing a semiconductor device and/or gatestructure, the methods may include forming a first conductive layer on asubstrate; removing an oxide layer formed on the first conductive layer;nitriding a surface of the first conductive layer to alter the surfaceinto a nitride layer; forming a composite dielectric layer on thenitride layer and/or forming a second conductive layer on the compositedielectric layer.

According to the semiconductor device, gate structure and methodprovided, a first conductive layer may be formed on a substrate. Anative oxide layer, which may be formed on the first conductive layer,may be removed. The native oxide layer may be removed using a dilutedhydrogen fluoride solution and/or a diluted hydrogen fluoride vapor.Alternatively, the native oxide layer may be removed by a dry etchingprocess using plasma.

A surface of the first conductive layer may be nitrided so that thesurface of the first conductive layer may be altered into a nitridelayer. The nitriding process may be a plasma nitriding process.Alternatively, the nitriding process may be a thermal nitriding process.The nitriding process may be performed under an ammonia atmosphereand/or a nitrogen atmosphere. A surface of a first conductive layer maybe nitrided so that current leakage and/or impurity penetration throughthe first conductive layer may be suppressed.

A composite dielectric layer may be formed on the nitride layer. Thecomposite dielectric layer may have a first dielectric layer and/or asecond dielectric layer. The first dielectric layer may include amaterial having a high dielectric constant. The second dielectric layermay be capable of suppressing crystallization of the first dielectriclayer. A second conductive layer may be formed on the compositedielectric layer.

To form the composite dielectric layer, the first dielectric layer maybe formed on the nitride layer by an atomic layer deposition using afirst oxidizer and/or a first reaction material that may includezirconium precursors. The zirconium precursor may be Zr[N(CH₃) (C₂H₅)]₄)and/or Zr(O-tBu)₄. These materials may be used alone or in a combinationthereof.

The second dielectric layer may be capable of suppressing thecrystallization of the first dielectric layer, which may be formed onthe first dielectric layer by an atomic layer deposition. The seconddielectric layer may have a crystallization temperature higher that thatof the first dielectric layer.

The second dielectric layer may include hafnium oxide and/or aluminumoxide. The second dielectric layer may be formed using a second oxidizerand/or a second reaction material. The second oxidizer may besubstantially the same as the first oxidizer. The second reactionmaterial may include hafnium precursors and/or aluminum precursors.

The hafnium precursor may be Hf[N(CH₃)₂]₄, Hf[N(C₂H₅)CH₃]₄),Hf[N(C₂H₅)₂]₄, Hf[OC(CH₃)₂CH₂OCH₃]₄ and/or Hf[OC(CH₃)₃]₄. Thesematerials may be used alone or in a combination thereof. The aluminumprecursor may be Al(CH₃)₃ and/or Al(C₂H₅)₃. These materials may be usedalone or in a combination thereof.

Processes for forming the first dielectric layer and/or processes forforming the second dielectric layer may be alternately performed atleast once. The first dielectric layer may have a thickness of about 0.5Å to about 10 Å. The second dielectric layer may have a thickness ofabout 0.5 Å to about 10 Å. The composite dielectric layer may have athickness of about 100 Å to about 500 Å.

According to the example embodiments of the present invention, acomposite layer may include a first dielectric layer of zirconium oxideand/or a second dielectric layer of hafnium oxide and/or aluminum oxide.The second dielectric layer may be formed on the first dielectric layer.

A crystallization temperature of hafnium oxide and/or aluminum oxide maybe higher than zirconium oxide. Thus, a crystallization temperature ofthe composite layer may be supplemented by the higher crystallizationtemperature of the second dielectric layer, which may include hafniumoxide and/or aluminum oxide.

The electrical characteristics of a semiconductor (e.g., a non-volatilememory device and/or a capacitor), employing the composite dielectriclayer, may be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments of the present invention will become readilyapparent by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings. FIGS. 1-17represent non-limiting example embodiments of the present invention asdescribed herein.

FIGS. 1 to 17 are cross-sectional views illustrating methods ofmanufacturing a semiconductor device and/or gate structure in accordancewith example embodiments of the present invention.

DESCRIPTION OF EXAMPLE EMBODIMENTS

Embodiments of the present invention will be described with reference tothe accompanying drawings. The present invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein. Rather, the embodiments areprovided so that disclosure of the present invention will be thoroughand complete, and will fully convey the scope of the present inventionto those skilled in the art. The principles and features of thisinvention may be employed in varied and numerous embodiments withoutdeparting from the scope of the present invention. In the drawings, thesize and relative sizes of layers and regions may be exaggerated forclarity. The drawings are not to scale. Like reference numerals refer tolike elements throughout.

It will be understood that when an element or layer is referred to asbeing “on”, “connected to” and/or “coupled to” another element or layer,the element or layer may be directly on, connected and/or coupled to theother element or layer or intervening elements or layers may be present.In contrast, when an element is referred to as being “directly on,”“directly connected to” and/or “directly coupled to” another element orlayer, there may be no intervening elements or layers present. As usedherein, the term “and/or” may include any and all combinations of one ormore of the associated listed items.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. These terms may beutilized to distinguish one element, component, region, layer and/orsection from another element, component, region, layer and/or section.For example, a first element, component, region, layer and/or sectiondiscussed below could be termed a second element, component, region,layer and/or section without departing from the teachings of the presentinvention.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like may be utilized to describe an element and/orfeature's relationship to another element(s) and/or feature(s) asillustrated in the figures. It will be understood that the spatiallyrelative terms are intended to encompass different orientations of thedevice in use and/or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” and/or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.The device may be otherwise oriented (rotated 90 degrees or at otherorientations) and the spatially relative descriptors used hereininterpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular terms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly-indicatesotherwise. It will be further understood that the terms “includes”and/or “including”, when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence and/or addition ofone or more other features, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein may have the same meaning as commonly understood byone of ordinary skill in the art. It will be further understood thatterms, such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and will not be interpreted in anidealized and/or overly formal sense unless expressly so defined herein.

Embodiments of the present invention are described with reference tocross-section illustrations that are schematic illustrations ofidealized embodiments of the present invention. As such, variations fromthe shapes of the illustrations as a result, for example, ofmanufacturing techniques and/or tolerances, are to be expected. Thus,embodiments of the present invention should not be construed as limitedto the particular shapes of regions illustrated herein but are toinclude deviations in shapes that result, for example, frommanufacturing. For example, an etched region illustrated as a rectanglewill, typically, have rounded or curved features. Thus, the regionsillustrated in the figures are schematic in nature of a device and arenot intended to limit the scope of the present invention.

FIGS. 1 to 14 are cross-sectional views illustrating methods ofmanufacturing a semiconductor device and/or gate structure in accordancewith example embodiments of the present invention.

Referring to FIG. 1, a substrate 100 (e.g., a silicon wafer) may bedivided into an active region and/or a field region by an isolationprocess. A top view of the field region may be a line shape. Theisolation process may be a shallow trench isolation (STI) process. Theisolation process may be a local oxidation of silicon (LOCOS) process.The isolation process may be a self-aligned shallow trench isolation(SA-STI) process. In the SA-STI process, a floating gate and/or theactive region may be formed simultaneously.

A thermal oxidation process may be performed on the substrate 100 toform a tunnel dielectric layer 102 on the substrate 100. The tunneldielectric layer 102 may have a thickness of about 50 Å to about 100 Å.The tunnel dielectric layer 102 may include silicon oxide and/or siliconoxynitride.

A preliminary first conductive layer (not shown), which may includepoly-silicon doped with impurities, may be formed on the tunneldielectric layer 102. Particularly, a poly-silicon layer having athickness of about 1,000 Å to about 1,500 Å may be formed on thesubstrate 100 by a low pressure chemical vapor deposition (LPCVD)process. Thereafter, the poly-silicon layer may be heavily doped withN-typed impurities by a doping process so that the preliminary firstconductive layer may be formed. The doping process may be a phosphorustetrachloride (POCl₃) diffusion process, an ion implantation processand/or an in-situ doping process.

Portions of the preliminary first conductive layer, the portions beingpositioned on the field region, may be removed by a photolithographyprocess so that a first conductive layer 104 may be formed on the activeregion. After the photolithography process is finished, a nitridingprocess may be performed on the first conductive layer 104.

Referring to FIG. 2, a native oxide layer (not shown), which may beformed on the first conductive layer 104, may be removed. The nativeoxide layer may have a thickness ranging from approximately a fewangstroms to approximately tens of angstroms. The native oxide layer maybe formed after the photolithography process and/or prior to a nitridingprocess. The native oxide layer may retard diffusion of nitrogen,therefore the native oxide layer may be removed before the nitridingprocess.

The native oxide layer may be removed by a wet etching process using adiluted hydrogen fluoride (HF) solution and/or a dry etching processthat may use a diluted hydrogen fluoride vapor. For example; the firstconductive layer 104, on which the native oxide layer may be formed, maybe dipped into the diluted hydrogen fluoride solution for about 1 minuteso that the native oxide layer may be removed. The diluted hydrogenfluoride solution may include deionized (DI) water and/or a purehydrogen fluoride solution. Particularly, a ratio of the DI water to thepure hydrogen fluoride solution may be about 200:1.

The native oxide layer may be removed by a dry etching process usingplasma. Particularly, a reaction gas, which may include a fluorinecompound, may be supplied onto the first conductive layer 104 through aremote plasma generator to remove the native oxide layer. The reactiongas may be a nitrogen trifluoride (NF₃) gas. The reaction gas may beintroduced into an etching chamber through the remote plasma generatorwith the aid of a carrier gas. The carrier gas may be a nitrogen gasand/or an argon gas. These gases may be used alone or in a combinationthereof. The dry etching process using the fluorine compound may beperformed at a temperature of about 15° C. to about 30° C. In removingthe native oxide layer, byproducts may be formed. In order to gasifyingthe byproducts, the byproducts may be thermally treated at a temperatureof about 100° C. to about 200° C. After the byproducts are gasified, thebyproducts may be efficiently exhausted from the etching chamber.

The native oxide layer may be removed by a plasma dry etching processusing a sputter. Particularly, an argon gas and/or a hydrogen gas may beintroduced into a plasma etching chamber. A radio frequency (RF) powermay be applied to an upper electrode of the plasma etching chamber sothat the argon gas and/or the hydrogen gas may have plasma states. An RFbias power may be applied to a lower electrode of the plasma etchingchamber, the lower electrode supporting the substrate 100, in order thatthe native oxide layer may be removed. The argon gas may be used forgenerating the plasma states. The hydrogen gas may be used for removingthe native oxide. A flow ratio of the argon gas to the hydrogen gas maybe about 1:9 to about 2:3. A temperature of the plasma etching chambermay be about 580° C. to about 700° C. A pressure of the plasma etchingchamber may be about 0.1 Torr to about 10 Torr.

After removal of the native oxide layer, the nitriding process may beperformed on the first conductive layer 104 so that a surface of thefirst conductive layer 104 may be altered into a nitride layer 106. Thenitriding process may be performed under an ammonia (NH₃) atmosphereand/or a nitrogen (N₂) atmosphere.

The nitriding process may be a plasma nitriding process and/or a thermalnitriding process. The plasma nitriding process may be performed at atemperature of about 300° C. to about 600° C. using an ammonia plasmagas and/or a nitrogen plasma gas. The thermal nitriding process may beperformed at a temperature of about 500° C. to about 1,000° C. using anammonia gas. The nitriding process may be performed for about 30 secondto about 10 minute. The nitride layer 106, formed by the nitridingprocess, may have a thickness of about 5 Å to about 20 Å. A surface ofthe nitride layer 106 may be altered into a silicon nitride layer if thefirst conductive layer 104 includes poly-silicon doped with impurities.

As shown in FIG. 10, a composite dielectric layer 130, which may includea first dielectric layer 110 (shown in FIG. 6) and/or a seconddielectric layer 120, may be formed on the nitride layer 106. The firstdielectric layer 110 and the second dielectric layer 120 may have afirst crystallization temperature and a second crystallizationtemperature, respectively. The second crystallization temperature may behigher that the first crystallization temperature. In other exampleembodiments, the first dielectric layer 110 may include zirconium oxide.The second dielectric layer 120 may include hafnium oxide and/oraluminum oxide. The composite dielectric layer 130 may be formed by anatomic layer deposition (ALD) process to a thickness of about 100 Å toabout 500 Å.

Hereinafter, processes for forming the composite dielectric layer 130 byusing the ALD process will be described. The nitride layer 106 isillustrated in FIGS. 3 to 10 for convenience in explanation. Thesubstrate 100, the tunnel dielectric layer 102, and the first conductivelayer 104 are omitted in FIGS. 3 to 10 for convenience in explanation.

Referring to FIG. 3, the substrate 100 may be transferred into a chamber10 used for performing the ALD process. If a temperature of the chamber10 is below about 150° C., reaction materials for forming the compositedielectric layer 130 may not be efficiently reacted with each other. Onthe other hand, if the temperature of the chamber 10 is above about 400°C., the composite dielectric layer 130 is rapidly crystallized. Thus,the temperature of the chamber 10 may be maintained at a temperature ofabout 150° C. to about 400° C. As one example, the temperature of thechamber 10 may be about 250° C. to about 350° C. When the temperature ofthe chamber 10 is about 250° C. to about 350° C., crystallization and/orslow reaction rates may be efficiently avoided. As another example, thetemperature of the chamber 10 may be about 300° C. When the temperatureof the chamber 10 is about 300° C., a deposition characteristic of theALD process may be efficiently achieved. If the pressure of the chamber10 is below about 0.1 Torr, the reaction materials for forming thecomposite dielectric layer 130 may not be efficiently reacted with eachother. On the other hand, if the pressure of the chamber is above about3.0 Torr, process conditions of the ALD process may not be efficientlycontrolled. That is, in this pressure range, the ALD process may beeasily controlled and/or a desired reaction rate may be achieved. Thus,The pressure of the chamber 10 may be about 0.1 Torr to about 3.0 Torr.

A first reaction material, which may include gaseous zirconiumprecursors, may be supplied onto the nitride layer 106. Particularly,the gaseous zirconium precursors may be supplied onto the nitride layer106 using a nitrogen gas and/or an argon gas. The nitrogen gas and/orthe argon gas may be used as a carrier gas. The gaseous zirconiumprecursors may be supplied onto the nitride layer 106 using a liquiddelivery system (LDS) and/or a bubbler system. The zirconium precursormay be Zr[N(CH₃) (C₂H₅)]₄ (tetrakis ethyl methyl amino zirconium, alsoknown as TEMAZ) and/or Zr(O-tBu)₄ (zirconium butyl oxide). Thesematerials may be used alone or in a combination thereof. The firstreaction material may be supplied onto the nitride layer 106 for about0.5 seconds to about 3 seconds. For example, the first reaction materialmay be supplied onto the nitride layer 106 for about 2 seconds.

The first reaction material may be divided into a first portion 112and/or a second portion 114. The first portion 112 of the first reactionmaterial may be chemically attached to the nitride layer 106. The secondportion 112 of the first reaction material may not be chemically bondedto the nitride layer 106. In another example embodiment, the secondportion 114 of the first reaction material may be physically attached tothe nitride layer 106 and/or the first portion 112. As another example,the second portion 114 of the first reaction material may float in thechamber 10.

Referring to FIG. 4, a purge gas may be supplied into the chamber 10.The purge gas may be an argon gas and/or a nitrogen gas. These gases maybe used alone or in a combination thereof. The purge gas may be suppliedinto the chamber 10 for about 0.5 seconds to about 5 seconds. Forexample, the purge gas may be supplied into the chamber 10 for about 2seconds.

The second portion 114 of the first reaction material may be exhaustedfrom the chamber 10 with the aid of the purge gas. For example, thesecond portion 114 of the first reaction material may be removed fromthe chamber 10 with the purge gas by using a vacuum pressure.

Referring to FIG. 5, a first oxidizer 116 may be supplied onto the firstportion 112 of the first reaction material, the first portion 112 beingchemically attached to the nitride layer 106. The first oxidizer 116 mayreact on the first portion 112 of the first reaction material so that afirst dielectric layer 110, which may include zirconium oxide, may beformed on the nitride layer 106. The first oxidizer 116 may be an ozone(O₃) gas, an oxygen (O₂) gas, a water vapor (H₂O) gas and/or a plasmaoxygen gas. These gases may be used alone or in a combination thereof.

In another example embodiment, the ozone gas may be used as the firstoxidizer 116. The ozone gas may be supplied onto the first portion 112of the first reaction material for about 1 second to about 5 seconds.For example, the ozone gas may be supplied onto the first portion 112 ofthe first reaction material for about 3 seconds.

Referring to FIG. 6, a purge gas may be supplied onto the firstdielectric layer 110 so that any unused oxidizer and/or byproducts,generated by reactions between the first portion 112 and/or the firstoxidizer 116, may be removed the chamber 10. The purge gas may besupplied for about 1 second to about 5 seconds. For example, the purgegas may be supplied for about 3 seconds. In an alternative exampleembodiment, the purge gas may be supplied until the unused oxidizerand/or byproducts are substantially removed.

The first dielectric layer 110, which may include zirconium oxide, mayhave the first crystallization temperature that may be relatively low.For example, the first crystallization temperature is about 400° C. Thefirst dielectric layer 110 may have a dielectric constant that may berelatively high. For example, the dielectric constant of the firstdielectric layer 110 is about 35. Because the first crystallizationtemperature is relatively low, it is not desirable to use the firstdielectric layer 110 alone even though the first dielectric layer hasthe relatively high dielectric constant.

Thus, according to example embodiments of the present invention, thesecond dielectric layer 120, having the second crystallizationtemperature higher than the first crystallization temperature of thefirst dielectric layer 110, may be formed on the first dielectric layer110.

Referring to FIG. 7, a second reaction material, which may includehafnium precursors and/or aluminum precursors, may be supplied onto thefirst dielectric layer 110 formed on the nitride layer 106. In supplyingthe second reaction material, a temperature of the chamber 10 and/or apressure of the chamber 10 may be constantly maintained. The secondreaction material may be divided into a first portion 122 and a secondportion 124. The first portion 122 of the second reaction material maybe chemically attached to the first dielectric layer 110. The secondportion 124 of the second reaction material may not be chemicallyattached to the first dielectric layer 110. In another exampleembodiment, the second portion 124 may be physically attached to thedielectric layer 110 and/or the first portion 122. In yet anotherexample embodiment, the second portion 124 may float in the chamber 10.

The hafnium precursor may be Hf[N(CH₃)₂]₄ (tetrakis dimethyl aminohafnium, also known as TDMAH), Hf[N(C₂H₅)CH₃]₄ (tetrakis ethyl methylamino hafnium, also known as TEMAH), Hf[N(C₂H₅)₂]₄ (tetrakis diethylamino hafnium, also known as TDEAH), Hf[OC(CH₃)₂CH₂OCH₃]₄ and/orHf[OC(CH₃)₃]₄. These materials may be used alone or in a combinationthereof. The aluminum precursor may be Al(CH₃)₃ (trimethyl aluminum;TMA) and/or Al(C₂H₅)₃ (triethyl aluminum; TEA). These materials may beused alone or in a combination thereof.

The second reaction material may be supplied onto the first dielectriclayer 110 for about 0.5 second to about 3 seconds. For example, thesecond reaction material may be supplied onto the first dielectric layer110 for about 2 seconds.

Referring to FIG. 8, a purge gas may be supplied into the chamber 10.The purge gas may be an inactive gas (e.g., a nitrogen gas).Alternatively, the purge gas may be an inert gas (e.g., an argon gas).The purge gas may be supplied into the chamber 10 for about 0.5 secondto about 5 seconds. For example, the purge gas may be supplied into thechamber 10 for about 2 seconds.

The second portion 124 of the second reaction material may be exhaustedfrom the chamber 10 with the aid of the purge gas. Particularly, thesecond portion 124 of the second reaction material may be removed fromthe chamber 10 with the purge gas by using a vacuum pressure.

Referring to FIG. 9, a second oxidizer 126 may be supplied onto thefirst portion 122 of the second reaction material. The second oxidizer126 may be substantially the same as the first oxidizer 116. Thus, anyfurther explanations will be omitted. A second dielectric layer 120,which may include hafnium oxide and/or aluminum oxide, may be formed onthe first dielectric layer 110 by reactions between the second oxidizer126 and/or the first portion 122 of the second reaction material. Thesecond oxidizer 126 may be an ozone gas, an oxygen gas, a water vaporgas and/or a plasma oxygen gas. These gases may be used alone or in acombination thereof.

According to yet another example embodiment, the ozone gas may be usedas the second oxidizer 126. The ozone gas may be provided onto the firstportion 122 of the second reaction material for about 1 second to about5 second. For example, the ozone gas may be supplied onto the firstportion 122 of the second reaction material for about 3 second.

Referring to FIG. 10, a purge gas may be supplied onto the seconddielectric layer 120 so that an unused oxidizer and/or byproducts,generated by reactions between the second oxidizer 126 and/or the firstportion 122 of the second reaction material, may be removed from thechamber 10. The purge gas may be supplied for about for about 1 secondto about 5 seconds. For example, the purge gas may be supplied for about3 seconds.

As a result, the composite dielectric layer 130, including the firstdielectric layer 110 and/or the second dielectric layer 120, may beformed on the nitride layer 106. The first dielectric layer 110 mayinclude zirconium oxide. The second dielectric layer 120 may includehafnium oxide and/or aluminum oxide.

Referring to FIG. 11, processes for forming the first dielectric layer110 and/or processes for forming the second dielectric layer 120 may berepeatedly performed until the composite dielectric layer 130 reaches adesired thickness. For example, the processes for forming the firstdielectric layer 110 may be repeatedly performed until the firstdielectric layer 110 has a total thickness of about 100 Å. In addition,the processes for forming the second dielectric layer 120 may berepeatedly performed until the second dielectric layer 120 has a totalthickness of about 100 Å. Thus, the composite dielectric layer 130 mayinclude more than two dielectric layers. In example embodiments, thesecond dielectric layer 120 may be formed on the first dielectric layer110 after the formation of the first dielectric layer 110.Alternatively, the first dielectric layer 110 may be formed on thesecond dielectric layer 120 after the formation of the second dielectriclayer 120.

In another example embodiment, as illustrated in FIG. 12, firstdielectric layers 110 a and/or the second dielectric layers 120 a mayalternately be formed on the nitride layer 106 to form a compositedielectric layer 130 a. In another example embodiment, the compositedielectric layer 130 a may include three or more dielectric layers. Inanother example embodiment, there may be more than one compositedielectric layer 130 a. Any or all of the composite dielectric layers130 a may have a laminated structure.

The first dielectric layer 110 may have a thickness of about 0.5 Å toabout 10 Å. The second dielectric layer 120 may have a thickness ofabout 0.5 Å to about 10 Å. The composite dielectric layer 130 a, whichmay include the first dielectric layers 110 and/or the second dielectriclayers 120, may have a thickness of about 100 Å to about 500 Å.

The first dielectric layer 110 a may be formed by processessubstantially the same as illustrated in FIGS. 3 to 6. Thus, any furtherexplanations will be omitted. The second dielectric layer 120 a may beformed by processes substantially the same as illustrated in FIGS. 7 to10. Thus, any further explanations will be omitted.

The second dielectric layer 120 a may have a crystallization temperaturehigher than the crystallization temperature of the first dielectriclayer 110 a. For example, the second dielectric layer may includehafnium oxide and/or aluminum oxide. A crystallization temperature ofhafnium oxide may be about 500° C. A crystallization temperature ofaluminum oxide may be about 600° C. Thus, in case that the firstdielectric layers 110 a and/or the second dielectric layers 120 a mayalternately be formed on the nitride layer 106 to form the compositedielectric layer 130 a, a crystallization temperature of the compositedielectric layer 130 a may be higher than that of the first dielectriclayer 110 a. As a result, crystallization of the composite dielectriclayer 130 a may be suppressed. Suppressing may include reducing,retarding, hindering and/or inhibiting crystallization. For example,when forming the first dielectric layers 110 a and/or the seconddielectric layers 120 a according to an atomic scale, thecrystallization temperature of the composite dielectric layer 130 a mayadjust to about 900° C.

Referring to FIG. 13, a second conductive layer 140 may be formed on thecomposite dielectric layer 130. The second conductive layer 140 mayinclude a doped poly-silicon layer which may or may not be doped withimpurities. The doped poly-silicon layer may be formed by an LPCVDprocess and/or an impurity doping process. The doped poly-silicon layermay have a thickness of about 1,000 Å. In addition, a metal silicidelayer (not shown) (e.g., a tungsten silicide (WSi) layer, a tantalumsilicide (TaSi) layer and/or a titanium silicide (TiSi) layer) may beformed on the doped poly-silicon layer. The metal silicide layer mayhave a thickness of about 100 Å to about 1,500 Å.

Referring to FIG. 14, the second conductive layer 140, the compositedielectric layer 130, the nitride layer 106, the first conductive layer104 and/or the tunnel dielectric layer 102 may be patterned to form acontrol gate electrode 150, a composite dielectric layer pattern 152, anitride layer pattern 154, a floating gate electrode 156 and/or a tunneldielectric layer pattern 158. Thus, a gate structure 160, which mayinclude the control gate electrode 150, the composite dielectric layerpattern 152, the nitride layer pattern 154, the floating gate electrode156 and/or the tunnel dielectric layer pattern 158, may be formed on thesubstrate 100. The gate structure 160 may be formed by an anisotropicetching process using an etch mask (not shown). Source/drain regions(not shown) may be formed in portions of a surface of the substrate 100,the portions being adjacent to the gate structure 160, so that anon-volatile memory device may be manufactured.

FIGS. 15 and 16 are cross-sectional views illustrating methods ofmanufacturing a semiconductor device in accordance with embodiments ofthe present invention.

Referring to FIG. 15, a tunnel dielectric layer 202 and/or a firstconductive layer 204 may be subsequently formed on a substrate 200(e.g., a silicon wafer). A native oxide layer, formed on the firstconductive layer 204, may be then removed. A nitriding process may beperformed on the first conductive layer 204 so that a surface of thefirst conductive layer 204 may be altered into a nitride layer 206.Processes for forming the tunnel dielectric layer 202, the firstconductive layer 204 and/or the nitride layer 206 may be substantiallythe same as illustrated in FIGS. 1 and 2. Thus, any further explanationswill be omitted.

A composite dielectric layer 210 having a laminated structure may beformed on the nitride layer 206. A first dielectric layer 212, which mayinclude zirconium oxide, a second dielectric layer 214, which mayinclude hafnium oxide, and/or a third dielectric layer 216, which mayinclude aluminum oxide, may be sequentially formed on the nitride layer206 by using an ALD process. In another example embodiment, the firstdielectric layer 212, the second dielectric layer 214 and/or the thirddielectric layer 216 may be sequentially formed over the nitride layer206 at least once. The first dielectric layer 212 may have a thicknessof about 0.5 Å to about 10 Å. The second dielectric layer 214 may have athickness of about 0.5 Å to about 10 Å. The third dielectric layer 216may have a thickness of about 0.5 Å to about 10 Å. The compositedielectric layer 210 may have a thickness of about 100 Å to about 500 Å.As described above, the third dielectric layer 216 may be stacked on thesecond dielectric layer 214. The second dielectric layer 214 may bestacked on the first dielectric layer 212. However, variations of astacking order of the first to third dielectric layers 212 to 216 are tobe appreciated. A second conductive layer 220 may be formed on thecomposite dielectric layer 210.

The first dielectric layer 212, the second dielectric layer 214 and/orthe third dielectric layer 216 may be formed by processes substantiallythe same as illustrated in FIGS. 3 to 12. Thus, any further explanationswill be omitted.

Referring to FIG. 16, the second conductive layer 220, the compositedielectric layer 210, the nitride layer 206, the first conductive layer204 and/or the tunnel dielectric layer 202 may be subsequently patternedto form a control gate electrode 230, a composite dielectric layerpattern 232, a nitride layer pattern 234, a floating gate electrode 236and/or a tunnel dielectric layer pattern 238. Thus, a gate structure240, which may include the control gate electrode 230, the compositedielectric layer pattern 232, the nitride layer pattern 234, thefloating gate electrode 236 and/or the tunnel dielectric layer pattern238, may be formed on the substrate 200. A source/drain region (notshown) may be formed in portions of a surface of the substrate 200, theportions being adjacent to the gate structure 240, so that anon-volatile memory device may be manufactured.

FIG. 17 is a cross-sectional view illustrating methods of manufacturinga semiconductor device in accordance with example embodiments of thepresent invention.

Referring to FIG. 17, a substrate 300 (e.g., a silicon wafer) may beprepared. The substrate 300 may include a semiconductor structure (notshown) (e.g., a gate structure, a source/drain and/or a bit line).

A first conductive layer 310 may be formed on the substrate 300, whichmay include the semiconductor structure. The first conductive layer 310may correspond to a lower electrode. The first conductive layer 310 mayor may not be formed using a poly-silicon doped with impurities. Thefirst conductive layer 310 may be formed by an LPCVD process. In anotherexample embodiment, the first conductive layer 310 may include a metaland/or a metal nitride. The metal may be titanium, ruthenium, tantalumand/or tungsten. The metal nitride may be titanium nitride, rutheniumnitride, tantalum nitride and/or tungsten nitride. As illustrated inFIG. 17, the first conductive layer 310 may have a plate shape.Alternatively, the first conductive layer 310 may have a cylindricalshape. If the first conductive layer 310 has a cylindrical shape, aneffective area of the first conductive layer 310 may be increased. Thefirst conductive layer 310 may be electrically coupled to an impurityregion formed in a surface of the substrate 300. For example, the firstconductive layer 310 may be electrically connected to a source/drainregion of a cell transistor of a dynamic random assess memory (DRAM)formed the substrate 300.

A native oxide layer formed on the first conductive layer 310 may beremoved. A nitriding process may be performed on the first conductivelayer 310 so that a surface of the conductive layer 310 may be alteredinto a nitride layer 320. Thereafter, a composite dielectric layer 330may be formed on the nitride layer 320 by using an ALD process.Particularly, a first dielectric layer 332, which may include zirconiumoxide, may be formed on the nitride layer 320. A second dielectric layer334, which may include hafnium oxide and/or aluminum oxide, may beformed on the first dielectric layer 332. A third dielectric layer (notshown), which may include aluminum oxide, may be formed on the seconddielectric layer 334, which may include hafnium oxide.

The composite dielectric layer 330 may be formed by processessubstantially the same as illustrated in FIGS. 3 to 12 and FIG. 15.Thus, any further explanations will be omitted.

A second conductive layer 340 may be formed on the composite dielectriclayer 330. The second conductive layer 340 may correspond to an upperelectrode. The second conductive layer 340 may or may not include apoly-silicon doped with impurities. Alternatively, the second conductivelayer 340 may include a metal and/or a metal nitride. The metal may betitanium, ruthenium, tantalum and/or tungsten. The metal nitride may betitanium nitride, ruthenium nitride, tantalum nitride and/or tungstennitride.

According to the example embodiments of the present invention, a nativeoxide layer, formed on a first conductive layer, may be removed so thata nitriding process may be more efficiently performed on the firstconductive layer. In addition, current leakage and/or an impuritypenetration through the first conductive layer may be retarded bynitriding the surface of the first conductive layer.

Furthermore, a composite dielectric layer may have a double-layeredstructure that may include a first dielectric layer and/or a seconddielectric layer. Thus, crystallization of the composite dielectriclayer may be suppressed. In addition, crystallization of the compositelayer may be more efficiently suppressed when the composite dielectriclayer includes a laminated structure in which the first dielectric layerand/or the second dielectric layer may be alternatively stacked. As aresult, the electrical characteristics of the semiconductor device maybe largely improved for a semiconductor (e.g., a non-volatile memorydevice, a capacitor, etc.) employing the composite dielectric layer.

The foregoing example embodiments are illustrative of the presentinvention and are not to be construed as limiting thereof. Although afew exemplary embodiments of this invention have been described, thoseskilled in the art will readily appreciate that many modifications arepossible in the exemplary embodiments without materially departing fromthe novel teachings and advantages of this invention. Accordingly, allsuch modifications are intended to be included within the scope of thisinvention as defined in the claims. Therefore, it is to be understoodthat the foregoing is illustrative of the present invention and is notto be construed as limited to the specific embodiments disclosed, andthat modifications to the disclosed embodiments, as well as otherembodiments, are intended to be included within the scope of theappended claims. The invention is defined by the following claims, withequivalents of the claims to be included therein.

1. A method of manufacturing a semiconductor device, the methodcomprising: forming a tunnel dielectric layer on a substrate forming afirst conductive layer on the tunnel dielectric layer; removing a nativeoxide layer from the first conductive layer; nitriding a surface of thefirst conductive layer to alter the surface into a nitride layer;forming a composite dielectric layer on the nitride layer, the compositedielectric layer having at least a first dielectric layer and a seconddielectric layer on the first dielectric layer, the second dielectriclayer including a material having a higher crystalline temperature thanthe first dielectric layer; forming a second conductive layer on thecomposite dielectric layer; and patterning the second conductive layer,the composite dielectric layer, the nitride layer, the first conductivelayer and the tunnel dielectric layer to form a gate structure includinga control gate electrode, a composite dielectric layer pattern, anitride layer pattern, a floating gate electrode and a tunnel dielectriclayer pattern.
 2. The method of claim 1, wherein nitriding is a plasmanitriding process performed at about 300° C. to about 600° C.
 3. Themethod of claim 1, wherein nitriding is a thermal nitriding processperformed at about 500° C. to about 1,000° C.
 4. The method of claim 1,wherein nitriding is performed under an ammonia atmosphere or a nitrogenatmosphere.
 5. The method of claim 1, wherein the first dielectric layerhas a higher dielectric constant than the second dielectric layer. 6.The method of claim 1, wherein forming the composite dielectric layerincludes forming the first dielectric layer on the nitride layer byatomic layer deposition using a first oxidizer and a first reactionmaterial that includes zirconium precursors, wherein the zirconiumprecursors are at least one selected from the group consisting ofZr[N(CH₃)(C₂H₅)]₄) and Zr(O-tBu)₄, and the first oxidizer is at leastone selected from a group consisting of O₃, O₂, H₂O and a plasma oxygengas.
 7. The method of claim 6, wherein the second dielectric layerincludes hafnium oxide or aluminum oxide.
 8. The method of claim 1,wherein forming the composite dielectric layer includes forming thesecond dielectric layer on the first dielectric layer by atomic layerdeposition, and wherein forming the second dielectric layer includesusing a second oxidizer and a second reaction material including hafniumprecursors or aluminum precursors, wherein the hafnium precursor is atleast one selected from the group consisting of Hf[N(CH₃)₂]₄,Hf[N(C₂H₅)CH₃]₄), Hf[N(C₂H₅)₂]₄, Hf[OC(CH₃)₂CH₂OCH₃]₄, Hf[OC(CH₃)₃]₄ andcombinations thereof, and the aluminum precursor is at least oneselected from the group consisting of Al(CH₃)₃, Al(C₂H₅)₃ andcombinations thereof.
 9. The method of claim 1, wherein forming thefirst dielectric layer and forming the second dielectric layer arealternately performed at least once.
 10. The method of claim 9, whereinthe first dielectric layer has a thickness of about 0.5 Å to about 10 Å;and the second dielectric layer has a thickness of about 0.5 Å to about10 Å.
 11. The method of claim 9, wherein the composite dielectric layerhas a thickness of about 100 Å to about 500 Å.
 12. The method of claim1, further comprising forming a third dielectric layer on the seconddielectric layer by an atomic layer deposition process, the thirddielectric layer having a crystallization temperature higher than thesecond dielectric layer.
 13. The method of claim 12, wherein the seconddielectric layer includes hafnium oxide and the third dielectric layerincludes aluminum oxide.
 14. The method of claim 1, wherein forming thecomposite dielectric layer is performed at a temperature of about 150°C. to about 400° C.
 15. The method of claim 1, wherein forming thecomposite dielectric layer is performed at a pressure of about 0.1 Torrto about 3.0 Torr.